package com.lagou.edu.factory;

import com.lagou.edu.anno.Autowired;
import com.lagou.edu.anno.Component;
import com.lagou.edu.anno.Transactional;
import com.lagou.edu.utils.TransactionManager;
import net.sf.cglib.proxy.Enhancer;
import net.sf.cglib.proxy.MethodInterceptor;
import net.sf.cglib.proxy.MethodProxy;

import java.lang.reflect.InvocationHandler;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;

/**
 * @author 应癫
 * <p>
 * <p>
 * 代理对象工厂：生成代理对象的
 */


@Component("proxyFactory")
public class ProxyFactory {


    @Autowired
    private TransactionManager transactionManager;


    /**
     * Jdk动态代理
     *
     * @param obj 委托对象
     * @return 代理对象
     */
    public Object getJdkProxy(Object obj) {

        // 获取代理对象
        return Proxy.newProxyInstance(obj.getClass()
                                         .getClassLoader(), obj.getClass()
                                                               .getInterfaces(),
                                      new InvocationHandler() {
                                          @Override
                                          public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
                                              Object result;
                                              Class<?> aClass = obj.getClass();
                                              Method declaredMethod = aClass.getDeclaredMethod(method.getName(), method.getParameterTypes());
                                              Class<?> parentClass = method.getDeclaringClass();
                                              if (parentClass.isAnnotationPresent(Transactional.class) && !aClass.isAnnotationPresent(
                                                      Transactional.class) && !method.isAnnotationPresent(Transactional.class) && !declaredMethod.isAnnotationPresent(
                                                      Transactional.class)) {
                                                  result = method.invoke(obj, args);
                                                  return result;
                                              }
                                              try {
                                                  // 开启事务(关闭事务的自动提交)
                                                  transactionManager.beginTransaction();

                                                  result = method.invoke(obj, args);

                                                  // 提交事务

                                                  transactionManager.commit();
                                              } catch (Exception e) {
                                                  e.printStackTrace();
                                                  // 回滚事务
                                                  transactionManager.rollback();

                                                  // 抛出异常便于上层servlet捕获
                                                  throw e;

                                              }

                                              return result;
                                          }
                                      });

    }


    /**
     * 使用cglib动态代理生成代理对象
     *
     * @param obj 委托对象
     * @return
     */
    public Object getCglibProxy(Object obj) {
        return Enhancer.create(obj.getClass(), new MethodInterceptor() {
            @Override
            public Object intercept(Object o, Method method, Object[] objects, MethodProxy methodProxy) throws Throwable {
                Object result;
                Class<?> proxyClass = o.getClass();
                if (!proxyClass.isAnnotationPresent(Transactional.class) && !method.isAnnotationPresent(Transactional.class)) {
                    result = method.invoke(obj, objects);
                    return result;
                }
                try {
                    // 开启事务(关闭事务的自动提交)
                    transactionManager.beginTransaction();

                    result = method.invoke(obj, objects);

                    // 提交事务

                    transactionManager.commit();
                } catch (Exception e) {
                    e.printStackTrace();
                    // 回滚事务
                    transactionManager.rollback();

                    // 抛出异常便于上层servlet捕获
                    throw e;

                }
                return result;
            }
        });
    }
}
